For example, Japanese Patent Application Publication No. 2016-205148 discloses a conventional ignition apparatus. A control circuit of the conventional ignition apparatus sends, to an ignition device, a discharge start signal indicative of an energization timing and de-energization timing to a primary coil.
In addition, the control circuit sends, to the ignition device, a discharge stop signal indicative of a stop timing of control of the discharge current carried out after the occurrence of a discharge in the spark plug.
The control circuit is configured to variably set a delay time of an input timing of the discharge stop signal to the ignition device relative to an input timing of the discharge start signal to the ignition device to thereby control a value of the discharge current based on the delay time.
When resetting the value of the discharge current after the value of the discharge current has been set, the control circuit reenters the discharge stop signal to the ignition device while the discharge start signal is in an on state to thereby update the delay time. This enables the control circuit to control the value of the discharge current without an increase of communication lines between the control circuit and the ignition device.